It's so much different from using audio amplifier and TV sweep vacuum
tubes in the final stages of low power transmitters. They were not
designed for that job. But they worked well (and still do). I am a fan
of those IRF510 and some others. 6BQ6, 6L6, 6AQ5, etc too.
73,
Bill KU8H
On Sat, 02 Jan 2021 14:11:29 -0800
"Jerry Gaffke via groups.io" <jgaffke@...> wrote:
Mad,
I think we're mostly on the same page here.
The uBitx is not a mil-spec radio, or anything close.
It's a rock bottom implementation of an all-band HF SSB rig,
inviting hacks to improve something, or perhaps to learn what not to
do.
I fully understand that in other arenas it matters to design by spec,
I've been there. However, there have been some excellent professional
RF engineers figuring out how to use the IRF510 for low cost amateur
builds. WA2EBY, W7ZOI, NA5N, and KB1GMX for starters.
I doubt any of them have used the IRF510 as an RF part in a product
at work, though I'm sure they all find joy in making a $0.50 part
work well as a 30mhz power amp.? Finding ways to do as much as
possible with a minimum of resources is a core part of much good
engineering.
I find it a perfect fit for the uBitx.? There are thousands of uBitx
users, I'd be surprised if more than 1% have tried moving to a
different FET. And I will speak up if somebody tries to make them
think they should.
If designing from scratch I wouldn't mess with the $2 Nano clones.
Better to just put down a modern $2 ARM QFP from Mouser.
But I haven't heard of anything better than the 40 year old IRF510
for use as a cheap RF amp.
Snowing here in far NE Oregon as well.
Forecast says we have snow on the menu for a week, temps in 20's and
30's. Have plenty to do, but this is a good excuse not to work
outside.
Jerry, KE7ER
On Sat, Jan 2, 2021 at 11:06 AM, MadRadioModder wrote:
This really is the same argument if you think about it.
The majors (Icom, Yaesu, Kenwood, etc.) don¡¯t use a nano or
nano-clone in their radios (actually some use sister chips)¡ not
because of the hardware per se¡ but because they don¡¯t want to
house and pay an entire army of firmware engineers on standby to
fix your meddling in their firmware. Thus its not a ¡°open¡± system¡
and using non-nano-like chips does aid in keeping the firmware
closed to the public and obscure. ??Most of us don¡¯t care because
the learning curve for all of the hardware they used would be large.
Trained RF engineers will start from system specifications and
design using the most cost-effective parts.? Now, to your point, on
this one¡ there really are no specifications on the uBITx, other
than what is on the HFSignals website¡ and that isn¡¯t much.? Maybe
Ashar just has not published them¡ or more likely¡ during the
design of the uBITx¡ he fiddled with parts in his basement until he
got something he liked.? No shame in that at all¡ witness the
number of uBITx owners.? But it is a different class of device from
one that is specified and designed from the ground up.
I won¡¯t be mentioning the RD series of devices in this forum
again.? Takes too much of my energy for nothing.
By the way, its showing here in Wisconsin today¡ Great day to be on
the radio!? See you there!
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